odd dns behavior on osx

sthaug at nethelp.no sthaug at nethelp.no
Sun Jun 20 15:54:56 CEST 2010

> >> You're experiencing a known OS X bug.  It will send out the A and AAAA
> >> queries in parallel, and will use the first answer it gets back and
> >> ignore the second one.  You probably get an NXDOMAIN response to your A
> >> request first, and therefore the AAAA response you're actually
> >> interested in gets ignored.
> > 
> > I believe you meant NODATA instead of NXDOMAIN here?
> The bug report says NXDOMAIN, but now that you mention it, I agree that
> NODATA would make more sense in order for it to be considered an OS X
> bug.  Perhaps the two just got confused.  Can't confirm it myself though
> as I don't own a Mac.

I believe the point here is that if you receive an NXDOMAIN response
to an A query, it says that neither A nor *any other* resource record
exists for the give name - and thus you cannot get an AAAA later.

If AAAA exists and A does not, NODATA is the correct response to an A

Steinar Haug, Nethelp consulting, sthaug at nethelp.no

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